PERFORATING BODIES FROM LOWER PALAEOZOIC ROOKS — ETHERIDGE 1 1 2 7 
Nostoc carnenm or N. commune * * * § and again N. hycdinum, f It 
would, perhaps, be out of place to call attention to the resemblance 
between endophytic chains of colls of Palaeozoic age, with a genus 
possessing a gelatinous thallus, or envelope, like Nogtoc, wore it 
not for the fact that Mr. A. 0. Seward has collected several in- 
stances where the cells of Nostoeaceje in chains have been found 
in calcareous pebbles at the bottom of lakes in Ireland, and in 
the State of Michigan, | The genera are Schizothvix , Nortec, 
Stiffonema , and Dichothrix , the lirst-nained enclosed in its com 
paratively hard tubular sheath. I have already stated that I 
believed I could distinguish, in move than one instance, a sheath 
or vagina, enclosing some of the moniliform chains. 
In the. Nostochineie, the triehome is either simple or branched; 
simple in the Nostocaceie, branched in the Scytonemea*, etc. In 
the present instance the triehome is decidedly branched, thus 
showing a departure from the Nost,oeaeo;e. furthermore, some 
genera at least of the Nostoohiuese contain marine species.^ As 
to the endophytic habit, it is known that species of Nostoc occur 
in the tissues, or mucilage-containing spaces of certain scale 
mosses. || 
In conclusion, and on the whole, it may perhaps he not too 
much to say that there is evidence of the existence in Paheozoic 
times of a jVbstoc-like endophytic alga, which, for systematic pur- 
poses, may he known as Pcd(BQpede% tohiteleggei. It is named in 
honour of Mr. Thomas Whitelcgge, of the Australian Museum, to 
whom I am indebted for several valuable suggestions. 
* Cooke — Brit. Fresh Water Alga), 1882-4, Atlas, pi. xc., fig. 2, pi. 
xci., fig. 5. 
t Bennett & Murray Handb. Crypt Hot., 1880, p. 481, fig. 359. 
j Seward Fossil Plants, i., 1808, p 122. 
§ Bennett & Murray — Handh. Crypt. But., 1880, p. 441 ; Seward - loc . 
cit., p. 122. 
|| Campbell — Mosses and Ferns, L895, pp. 115, 117, 110, 122, etc. 
11 7 rc 8 > 7 , a chain or fetter. 
